Which of the following statements regarding the regulation of gastrointestinal motility is true?
**Core Concept**
Gastrointestinal (GI) motility is a complex process regulated by a network of neurons, hormones, and the enteric nervous system. The regulation of GI motility is crucial for the proper digestion and absorption of nutrients.
**Why the Correct Answer is Right**
The correct answer involves the interaction between the enteric nervous system and the hormone gastrin. The enteric nervous system, also known as the "little brain," controls GI motility through the release of neurotransmitters such as acetylcholine and serotonin. Gastrin, a hormone released from G cells in the antrum of the stomach, stimulates the release of gastric acid and also enhances GI motility by stimulating the release of acetylcholine from the enteric nervous system. This leads to the contraction of smooth muscle in the stomach and small intestine, facilitating the movement of food through the digestive system.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect because while gastrin does stimulate the release of gastric acid, it is not the primary regulator of GI motility.
* **Option B:** This option is incorrect because the hormone cholecystokinin (CCK) primarily regulates the release of digestive enzymes and the contraction of the gallbladder, rather than GI motility.
* **Option D:** This option is incorrect because the hormone secretin primarily regulates the release of bicarbonate from the pancreas and the bile ducts, rather than GI motility.
**Clinical Pearl / High-Yield Fact**
Remember that the enteric nervous system plays a crucial role in regulating GI motility, and disturbances in this system can lead to conditions such as irritable bowel syndrome (IBS) and gastroparesis.
**Correct Answer: C. Gastrin stimulates the release of acetylcholine from the enteric nervous system, enhancing GI motility.**